With a progress of a digital image processing technology and an equipment manufacturing level, 3D display has become a major trend in display industry. A basic principle of the current 3D display is “parallax type stereoscopic display”. Specifically, a viewer is made to watch two different images using a certain equipment or a technology. That is, a left eye is made to watch only a left image, and a right eye is made to watch only a right image. The left image and the right image are images of a spatial object that are taken from two different angles. The left image and the right image are referred to as a stereoscopic image pair. Then, a human brain will combine the two images watched by the two eyes together to produce a 3D effect.
3D display according to the prior art is divided into glasses-wearing type and naked-eye type. Glasses-wearing type requires the viewer to wear 3D glasses to get 3D display effect. But the wearing of glasses adversely affects an experience feeling of the viewer, limits a freedom of the viewer, and substantially affects an experience feeling of a viewer who has myopia or hyperopia. The naked-eye type includes a parallax barrier type, a cylindrical lens grating type, a liquid crystal grating type. The prior art discloses a grating-type 2D/3D switching apparatus. The grating-type 2D/3D switching apparatus includes a deformed cylindrical lens grating and a 2D display device. The deformed cylindrical lens grating stores two kinds of immiscible transparent liquid. The two kinds of transparent liquid have different refractive indexes, and have similar or identical densities. A transparent elastic film is used to separate the two kinds of transparent liquid. Both surfaces of the elastic film have multiple transparent support plates to support the elastic film. The deformation of the elastic film is achieved and controlled by a liquid flow driven by an external force and a supporting by the support plates. The elastic film has two states including a flat shape state and a cylindrical shape state. The 2D/3D display switching is achieved by the state switching of the elastic film. In actual use, this kind of switching apparatus is highly unstable, and the structure of the switching apparatus is very complicated and is difficult to be implemented.